In the prior art, primarily a conventional and proven twin disk bearing (roller bearing) was used as the bearing of a spinning rotor. In this case, the spinning rotor is at the end of a shaft which runs between a drive belt and two rollers which have diameters at least 10 times greater than the diameter of the shaft and which are lined with rubber. In view of this translation ratio of 1:10, the life of the ball bearing could be extended considerably over that of a direct ball bearing of the spinning shaft, where a 10 times greater speed of the ball bearings is necessary. Nevertheless, the rollers and the ball bearings must be renewed approximately every 20,000 hours because of wear.
The twin disk bearing offers however clear advantages over earlier bearings. Specifically, since it is able to bear relatively great loads and because of the rubber lining on the rollers and the drive via a belt, the shaft with the spinning rotor runs in the supercritical range, so that the unbalance forces exerted upon the bearing are considerably lower. This bearing is described in detail in the document laid open to public inspection, German Patent Application No. DE 25 25 435 B1. In the apparatus described in this document, a support bearing (see column 4, uppermost paragraph) is also present, but in an entirely different context from that of the bearing designated at 4 and described in the claims.
Furthermore, in this connection the use of aerostatic bearings has often been tried, as no wear of the bearing occurs with them. As the document laid open to public inspection German Patent Application No. DE-AS 23 49 072 describes, the rotor is rigidly connected to the supported shaft in this case, and therefore this bearing is unable to support the high loads caused by unbalance in the spinning rotor when a yarn breakage occurs.
Where varnish atomization is used, for example, and in spite of the aerostatic bearing which is often used, rigid connection between the atomizer and the rotating shaft is still customary, so that low unbalance masses or a slightly eccentric seat of the atomizer on the shaft can already cause the aerostatic bearing to become overloaded. Since the ability of gas bearings to bear loads as compared to roller bearings of the same size is many times lower, their utilization was often not possible until now. Furthermore, even a slight overload of the gas bearing at high rotational speeds causes irreparable malfunction.
In addition to spinning rotors, a gas bearing is desirable also with other rapidly rotating tools. Such tools are for example the head of a varnish atomizers, the drum of a centrifuge and optical tools such as prisms, polygons etc. Instead of air, other gases can and should also be used for the bearing. The bearing should and can be static or dynamic.